boyfriend is concerned

Hi my name is Jackie and I just found out that I'm 5weeks 6days going into my 6week. My boyfriend keeps asking me are you sure it's ok that we have sex while your pregnant is scare is because he is 9" I have asked my ob and she said yes as long as it's comfortable but is it ok to have sex while I'm pregnant? I'm ready to just jump his dick when I see him but if it's not safe then I don't want to because I don't want to harm my baby. Can anyone help? Is sex while pregnant ok?